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Danfo.js Documentation
Getting Started
API reference
General Functions
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Series
Dataframe
Creating a DataFrame
DataFrame.sortIndex
DataFrame.append
DataFrame.nUnique
DataFrame.tensor
DataFrame.print
DataFrame.toCSV
DataFrame.toJSON
DataFrame.toExcel
DataFrame.sortValues
DataFrame.setIndex
DataFrame.resetIndex
DataFrame.rename
DataFrame.drop
DataFrame.asType
DataFrame.shape
DataFrame.axis
DataFrame.ndim
DataFrame.values
DataFrame.selectDtypes
DataFrame.ctypes
DataFrame.index
DataFrame.loc
DataFrame.iloc
DataFrame.at
DataFrame.iat
DataFrame.head
DataFrame.tail
DataFrame.sample
DataFrame.add
DataFrame.sub
DataFrame.mul
DataFrame.div
DataFrame.pow
DataFrame.mod
DataFrame.mean
DataFrame.median
DataFrame.min
DataFrame.max
DataFrame.std
DataFrame.var
DataFrame.count
DataFrame.round
DataFrame.cumSum
DataFrame.cumMin
DataFrame.cumMax
DataFrame.cumProd
DataFrame.copy
DataFrame.describe
DataFrame.sum
DataFrame.abs
DataFrame.query
DataFrame.addColumn
DataFrame.groupby
DataFrame.column
DataFrame.fillNa
DataFrame.isNa
DataFrame.dropNa
DataFrame.apply
DataFrame.applyMap
DataFrame.It
DataFrame.gt
DataFrame.le
DataFrame.ge
DataFrame.ne
DataFrame.eq
DataFrame.replace
Configuration Options
Plotting
Groupby
User Guides
Building Data Driven Applications with Danfo.js - Book
Contributing Guide
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DataFrame.groupby
Group DataFrame using a mapper or by a Series of columns.
danfo.DataFrame.
groupby
(columns)
Parameters
Type
Description
Default
columns
Array
The names of a column(s) in the DataFrame to group by
Examples
Groupby a single column from a DataFrame
Node
Browser
1
const
dfd
=
require
(
"danfojs-node"
)
2
3
let
data
=
[[
"Pear"
,
2
,
3
],
[
"Pear"
,
5
,
6
],
[
"Apple"
,
30
,
40
],
[
"Apple"
,
89
,
78
]]
4
let
cols
=
[
"A"
,
"B"
,
"C"
]
5
6
let
df
=
new
dfd
.
DataFrame
(
data
,
{
columns
:
cols
})
7
let
group_df
=
df
.
groupby
([
"A"
])
8
console
.
log
(
group_df
)
Copied!
1
// ouput
2
Groupby {
3
colDict: {
4
Pear: { A: [Array], B: [Array], C: [Array] },
5
Apple: { A: [Array], B: [Array], C: [Array] }
6
},
7
keyToValue: { Pear: [ 'Pear' ], Apple: [ 'Apple' ] },
8
keyCol: [ 'A' ],
9
data: [
10
[ 'Pear', 2, 3 ],
11
[ 'Pear', 5, 6 ],
12
[ 'Apple', 30, 40 ],
13
[ 'Apple', 89, 78 ]
14
],
15
columnName: [ 'A', 'B', 'C' ],
16
colDtype: [ 'string' ],
17
colIndex: [ 0 ]
18
}
Copied!
1
Copied!
A groupby operation will return a GroupBy class object. You can apply any of the following operation on the groupby result:
1.
count
2.
sum
3.
std
4.
var
5.
mean
6.
cumSum
7.
cumMax
8.
cumProd
9.
cummin
10.
max
11.
min
Example of Groupby and apply a sum function
Node
1
const
dfd
=
require
(
"danfojs-node"
)
2
3
let
data
=
[[
"Pear"
,
2
,
3
],
[
"Pear"
,
5
,
6
],
[
"Apple"
,
30
,
40
],
[
"Apple"
,
89
,
78
]]
4
let
cols
=
[
"A"
,
"B"
,
"C"
]
5
let
df
=
new
dfd
.
DataFrame
(
data
,
{
columns
:
cols
})
6
let
group_df
=
df
.
groupby
([
"A"
]).
sum
()
7
8
group_df
.
print
()
Copied!
1
╔════════════╤═══════════════════╤═══════════════════╤═══════════════════╗
2
║ │ A │ B_sum │ C_sum ║
3
╟────────────┼───────────────────┼───────────────────┼───────────────────╢
4
║ 0 │ Pear │ 7 │ 9 ║
5
╟────────────┼───────────────────┼───────────────────┼───────────────────╢
6
║ 1 │ Apple │ 119 │ 118 ║
7
╚════════════╧═══════════════════╧═══════════════════╧═══════════════════╝
Copied!
Groupby a two columns from a DataFrame
Node
Browser
1
const
dfd
=
require
(
"danfojs-node"
)
2
3
let
data
=
[[
"Pear"
,
2
,
3
],
[
"Pear"
,
2
,
6
],
[
"Apple"
,
30
,
40
],
[
"Apple"
,
89
,
78
]]
4
let
cols
=
[
"A"
,
"B"
,
"C"
]
5
let
df
=
new
dfd
.
DataFrame
(
data
,
{
columns
:
cols
})
6
let
group_df
=
df
.
groupby
([
"A"
,
"B"
]).
sum
()
7
8
group_df
.
print
()
Copied!
1
Copied!
1
╔════════════╤═══════════════════╤═══════════════════╤═══════════════════╗
2
║ │ A │ B │ C_sum ║
3
╟────────────┼───────────────────┼───────────────────┼───────────────────╢
4
║ 0 │ Pear │ 2 │ 9 ║
5
╟────────────┼───────────────────┼───────────────────┼───────────────────╢
6
║ 1 │ Apple │ 30 │ 40 ║
7
╟────────────┼───────────────────┼───────────────────┼───────────────────╢
8
║ 2 │ Apple │ 89 │ 78 ║
9
╚════════════╧═══════════════════╧═══════════════════╧═══════════════════╝
Copied!
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DataFrame.addColumn
Next
DataFrame.column
Last modified
5mo ago
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Contents
Examples
Groupby a single column from a DataFrame
Example of Groupby and apply a sum function
Groupby a two columns from a DataFrame